scholarly journals Spatiotemporal Evolution of Earthquakes in Longmenshan Fault and Adjacent Area, before and after the 2008 Wenchuan Earthquake

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Gang Fan ◽  
Jun Wang ◽  
Shunchao Qi ◽  
Gongda Lu ◽  
Xingguo Yang ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Seismogenic Zone ◽  
Adjacent Area ◽  
Spatiotemporal Evolution ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
The Wenchuan Earthquake ◽  
Before And After ◽  
Longmenshan Fault ◽  
International Seismological Centre

Seismicity sequence following a main earthquake usually contains much meaningful information for unveiling the focal mechanism and predicting the reoccurrence interval of large earthquakes. The spatiotemporal evolution of earthquakes before and after the 2008 Wenchuan earthquake (Ms 8.0) is analysed comprehensively in this study. The frequency-magnitude relation of the 3493 earthquake events retrieved from the database of the International Seismological Centre indicates that the adopted catalogue is complete for magnitudes ≥Ms 3.4. The seismicity during the 10 years before the Wenchuan earthquake remained stable, including the magnitudes and focal depths. However, seismicity attenuated sharply in the year following the Wenchuan earthquake, and the magnitude of earthquakes before the Wenchuan earthquake decreased gradually. The area of the seismogenic zone of the 2008 Wenchuan earthquake was smaller than the earthquake stricken area. The earthquakes that occurred in the Longmenshan fault area and adjacent area in the study period were mainly shallow earthquakes. The focal depths of earthquakes in the study area became stable gradually after the Wenchuan earthquake, mainly within the range from 10 to 16 km. The earthquakes in the study area were mainly distributed with an along-dip distance of 0–20 km, and the seismicity was distributed uniformly along the fault strike.

scholarly journals Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7110 ◽  
Author(s):  
Fei Zhang ◽  
Zhangdong Jin ◽  
A. Joshua West ◽  
Zhisheng An ◽  
Robert G. Hilton ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Transport Processes ◽  
Delayed Response ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Depositional Processes ◽  
Before And After ◽  
Sediment Transfer ◽  
Large Earthquakes ◽  
Earthquake Cycles

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake’s sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

Eikonal Equation-Based Seismic Tomography of the Source Areas of the 2008 Mw 7.9 Wenchuan Earthquake and the 2013 Mw 6.6 Lushan Earthquake

2020 ◽  
Vol 110 (2) ◽  
pp. 886-897
Author(s):  
Jun Li ◽  
Hui Li ◽  
Hui Chen ◽  
Jinrong Su ◽  
Yongsheng Liu ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
High Velocity ◽  
Lushan Earthquake ◽  
Low Velocity ◽  
Longmenshan Fault Zone ◽  
2008 Wenchuan Earthquake ◽  
Velocity Anomaly ◽  
The 2008 Wenchuan Earthquake ◽  
Longmenshan Fault ◽  
2013 Lushan Earthquake

ABSTRACT We use the eikonal equation-based seismic travel-time tomography method to image the source areas of the 2008 Wenchuan earthquake and the 2013 Lushan earthquake in the Longmenshan fault zone. High-resolution VP and VS models are obtained by inverting 75,686 P-wave and 74,552 S-wave travel times of local earthquakes during the period from 2009 to 2018. The tomographic models reveal strong crustal velocity heterogeneities in the study area. A significant velocity contrast exists across the Longmenshan fault zone: The western Songpan–Ganzi block is a high-velocity body, whereas the eastern Sichuan basin is a low-velocity anomaly. The hypocenter of the 2008 Wenchuan earthquake is between a high-velocity and a low-velocity anomaly. Beneath the Wenchuan mainshock, there is a significant low-velocity structure in the lower crust. The 2013 Lushan earthquake occurred in rocks associated with a high-velocity anomaly. A distinct low-velocity zone with low seismicity is imaged between the 2008 Wenchuan earthquake and the 2013 Lushan earthquake, where the crustal ductile deformation is likely to occur. The Baoxing complex to the northwest of the Lushan hypocenter exhibits as a high-velocity anomaly, which may be a carrier of stress accumulation and more prone to seismic activities in the future.

scholarly journals Deep structure of the Longmenshan fault zone and mechanism of the 2008 Wenchuan earthquake

2018 ◽  
Vol 63 (19) ◽  
pp. 1906-1916 ◽  
Author(s):  
Jianshe Lei ◽  
Dapeng Zhao ◽  
Xiwei Xu ◽  
Mofei Du ◽  
Guangwei Zhang ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Fault Zone ◽  
Deep Structure ◽  
Longmenshan Fault Zone ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Longmenshan Fault
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